1. Field of the Invention
The present invention relates to a sunglass lens used mainly in sunglasses and goggles, to a method for producing the lens, and to a production apparatus for obtaining the sunglass lens by using the method.
2. Description of the Related Art
In recent sunglasses, fashionable appearance is of particular importance. In consideration of this, sunglasses are designed with a narrow width shape as shown in FIG. 16. In such type of sunglasses, in order to provide a function of blocking not only light L1 incident from the front thereof but also light L2 incident from the side thereof, each lens A is largely bent such that the end portion thereof extends to the side of the face of a wearer.
Recently, as a polarizing sunglass lens having a curved shape shown in FIG. 16, a lens has been proposed which has an aspherical lens surface formed by bending a laminated plate produced by laminating a polycarbonate supporting layer to both sides of a thin polarizing layer (see, for example, Publication of Japanese Patent No. 3130510).
This polarizing lens has an aspheric curved lens surface having the degree of curvature of a curved surface along a polarization axis larger than that of a curved surface along the direction orthogonal to the polarization axis and is formed to have, for example, an 8R×5R curved surface. Here, a degree of curvature of “1R” means that the radius of curvature is 523 mm, and the value representing the degree of curvature is inversely proportional to the radius of curvature. Therefore, the larger the radius of curvature becomes, the gentler the curve becomes. On the other hand, the larger the above value becomes, the steeper the curve becomes.
Since this polarizing lens is largely bent along the polarization axis, the lens can block light incident from the side thereof. However, since the lens is bent with a constant radius of curvature, the curved lens surface does not conform to and fit the face of a wearer. Recently, the design of sunglasses is increasingly sophisticated, and there is a demand for sunglasses which fit the face. However, the abovementioned polarizing lens for sunglasses cannot be formed into a shape which adequately fits the face. Thus, the demand cannot be adequately satisfied.
For sunglasses having a frame, even when an eyeglass frame which conforms the face of a wearer is produced, it is difficult to insert a polarizing lens into the eyeglass frame. In order to satisfy the demand, sunglasses have been proposed which have an eyeglass frame B into which front lenses A1 and side lenses A2 are separately inserted as shown in FIG. 17. However, such sunglasses are expensive since the production process is complicated, and a frame C between the front lens A1 and the side lens A2 obstructs the view of a wearer to cause a visibility problem.